Marine propulsion system and method for preventing collision of marine propulsion devices

ABSTRACT

A marine propulsion system for a marine vessel includes a first marine propulsion device rotatable with respect to the marine vessel about at least one of a first steering axis and a first tilt-trim axis and a second marine propulsion device rotatable with respect to the marine vessel about at least one of a second steering axis and a second tilt-trim axis. A first control module controls operation of the first marine propulsion device, and a second control module controls operation of the second marine propulsion device. In response to one of the first and second marine propulsion devices being commanded to rotate about at least one of its respective first or second steering axis and its respective first or second tilt-trim axis, the respective first or second control module of the other of the first and second marine propulsion devices is turned ON.

FIELD

The present disclosure relates to marine vessels having marinepropulsion systems including two or more marine propulsion devices.

BACKGROUND

U.S. Pat. No. 8,818,587 discloses methods and systems for controllingmovement of at least one propulsion unit on a marine vessel. The methodcomprises plotting a first plurality of points representing a firstsurface of a first propulsion unit and plotting a second plurality ofpoints representing a second surface. The method further compriseslimiting movement of at least the first propulsion unit such that thefirst surface does not come within a predetermined distance of thesecond surface during said movement.

Unpublished U.S. patent application Ser. No. 15/378,778, filed Dec. 14,2016, discloses a marine propulsion system including an outboard motor.The outboard motor has a cowl covering an internal combustion enginethat is coupled to and powers a propeller. A motion sensor and anorientation sensor are coupled to the outboard motor, such as to theengine or the cowl. A control module is in signal communication with themotion sensor and the orientation sensor. The motion sensor andorientation sensor respectively provide information regarding anacceleration and an orientation of the engine or the cowl to the controlmodule. A direction sensor and a GPS receiver may also be provided onthe engine or the cowl, and may also be in signal communication with thecontrol module. Information regarding the vessel's acceleration,orientation, direction, and global position can be used to controlfeatures of the propulsion system.

SUMMARY

This Summary is provided to introduce a selection of concepts that arefurther described herein below in the Detailed Description. This Summaryis not intended to identify key or essential features of the claimedsubject matter, nor is it intended to be used as an aid in limiting thescope of the claimed subject matter.

According to one example of the present disclosure, a marine propulsionsystem for a marine vessel includes a first marine propulsion devicerotatable with respect to the marine vessel about at least one of afirst steering axis and a first tilt-trim axis and a second marinepropulsion device rotatable with respect to the marine vessel about atleast one of a second steering axis and a second tilt-trim axis. A firstcontrol module controls operation of the first marine propulsion device,and a second control module controls operation of the second marinepropulsion device. In response to one of the first and second marinepropulsion devices being commanded to rotate about at least one of itsrespective first or second steering axis and its respective first orsecond tilt-trim axis, the respective first or second control module ofthe other of the first and second marine propulsion devices is turnedON.

According to another example of the present disclosure, a method for amarine propulsion system for a marine vessel is carried out by a controlmodule and includes determining at least one of the following:

-   -   (a) whether a first marine propulsion device rotatable with        respect to the marine vessel about at least one of a first        steering axis and a first tilt-trim axis is keyed ON;    -   (b) whether a second marine propulsion device rotatable with        respect to the marine vessel about at least one of a second        steering axis and a second tilt-trim axis is keyed ON;    -   (c) whether the first marine propulsion device is commanded to        rotate about at least one of its first steering axis and its        first tilt-trim axis; and    -   (d) whether the second marine propulsion device is commanded to        rotate about at least one of its second steering axis and its        second tilt-trim axis.        In response to at least one of (a), (b), (c), and (d) being        true, the method includes turning on a first control module        controlling operation of the first marine propulsion device and        a second control module controlling operation of the second        marine propulsion device.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is described with reference to the followingFigures. The same numbers are used throughout the Figures to referencelike features and like components.

FIG. 1 illustrates a marine vessel having a marine propulsion system.

FIG. 2 is a schematic showing additional components of the marinepropulsion system.

FIG. 3 is a schematic showing electrical connections between componentsof the marine propulsion system.

FIG. 4 shows a method for a marine propulsion system according to thepresent disclosure.

DETAILED DESCRIPTION

In the present description, certain terms have been used for brevity,clarity, and understanding. No unnecessary limitations are to be impliedtherefrom beyond the requirement of the prior art because such terms areused for descriptive purposes only and are intended to be broadlyconstrued. The different systems and methods described herein may beused alone or in combination with other systems and methods. Variousequivalents, alternatives, and modifications are possible.

FIG. 1 illustrates a marine vessel 10 having a marine propulsion system12 including a first marine propulsion device 14 and a second marinepropulsion device 16. The first marine propulsion device 14 is rotatablewith respect to the marine vessel 10 about at least one of a firststeering axis 18 and a first tilt-trim axis 20. The second marinepropulsion device 16 is rotatable with respect to the marine vessel 10about at least one of a second steering axis 22 and a second tilt-trimaxis 24. As is known, the first and second propulsion devices 14, 16produce first and second thrusts to propel the marine vessel 10 by wayof first and second engines 26, 28 powering first and second propellers30, 32 via first and second transmissions 34, 36, respectively. Asillustrated in FIG. 1, the first and second marine propulsion devices14, 16 are outboard motors, but they could alternatively be inboardmotors, stern drives, jet drives, or pod drives. In the example in whichthe marine propulsion devices 14, 16 are outboard motors, the first andsecond steering axes 18, 22 are generally vertically oriented when themarine propulsion devices 14, 16 are in a neutral trim position, and thefirst and second tilt-trim axes 20, 24 are generally horizontallyoriented. In one example, the gear cases of the outboard motors aresteerable independently of the upper cowls and midsections of theoutboard motors.

The marine propulsion system 12 also includes various control elementsfor controlling marine vessel and marine propulsion device functions,such as, but not limited to, operational mode, direction, speed,steering, tilt, and trim. For example, the marine propulsion system 12comprises an operation console 38 (helm) in signal communication withone or more control modules, such as for example a helm control module(HCM) 40 and electronic control modules (ECM) 42, 44 associated with therespective marine propulsion devices 14, 16. The ECM 42 is a firstcontrol module controlling operation of the first marine propulsiondevice 14, while the ECM 44 is a second control module controllingoperation of the second marine propulsion device 16. The ECMs 42, 44 maycontrol the engines 26, 28 and transmissions 34, 36 of the marinepropulsion devices 14, 16 as well as their steering and tilt-trimorientations. In other examples of the marine propulsion system 12, twoHCMs are provided, one for each marine propulsion device 14, 16. SeeFIG. 3.

The operation console 38 includes a number of user input devices, suchas an interactive display screen 46, a joystick 48, a steering wheel 50,and throttle/shift levers 52. Each of these input devices can be used toinput commands to the HCM 40. The HCM 40 in turn communicates with thefirst and second propulsion devices 14, 16, for example, bycommunicating with the ECMs 42, 44. It should be understood that inalterative examples, the various input devices 46, 48, 50, 52 maycommunicate directly with the ECMs 42, 44. The interactive displayscreen 46 may have touch capabilities and/or be provided with anassociated keypad or keyboard that allows an operator of the marinevessel 10 to input various commands and/or select various modes ofoperation associated with the marine vessel 10. The joystick 48 allowsthe operator to maneuver the marine vessel 10 forward and back,laterally side-to-side, and diagonally, as well as to rotate (yaw). Thesteering wheel 50 and throttle/shift levers 52 are used together tocommand a direction and magnitude of thrust from the marine propulsiondevices 14, 16, as well as a direction of travel for the marine vessel10. For example, rotation of the steering wheel 50 activates atransducer that provides a signal to the HCM 40 regarding a desireddirection of the marine vessel 10. The HCM 40 in turn sends signals tothe ECMs 42, 44, which in turn activate steering actuators 63, 64 (FIG.2) to achieve a desired orientation of the marine propulsion devices 14,16. The throttle/shift levers 52 send signals to the HCM 40 regardingthe desired gear (forward, reverse, or neutral) of the transmissions 34,36 and the desired rotational speed of the engines 26, 28. The HCM 40 inturn sends signals to the ECMs 42, 44, which in turn activate shift andthrottle electromechanical actuators in the transmissions 34, 36 andengines 26, 28, respectively.

FIG. 2 shows a schematic of the marine propulsion system 12 withadditional detail. In the example shown, the marine propulsion system 12includes the above-mentioned throttle/shift levers 52, joystick 48,interactive display screen 46, steering wheel 50, HCM 40, marinepropulsion devices 14, 16, and ECMs 42, 44. Additionally, a keypad 54 isprovided at the operation console 38, which allows the operator tocommand the marine propulsion devices 14, 16 to tilt and trim abouttheir respective tilt-trim axes 20, 24. For example, the operator canpress the UP button 54 a to rotate the marine propulsion device 14, 16up away from the transom of the marine vessel 10. The operator can pressthe DOWN button 54 b to rotate the marine propulsion device 14, 16 downtoward the transom. The operator can instead select an AUTO button 54 cto automatically trim the marine propulsion devices 14, 16 according topredefined algorithms based on vessel and/or engine speed, vesselattitude in the water, etc. In one example, two keypads 54 are provided,one for controlling the tilt and trim position of each respective marinepropulsion device 14, 16. In some examples, separate buttons might beprovided for tilting the marine propulsion devices 14, 16 than fortrimming them, it being understood that a tilt angle of a marinepropulsion device is generally greater than a maximum trim anglethereof. For example, the maximum trim angle might be one at which thepropeller 30 or 32 is at a functional depth in the water for propellingthe marine vessel 10, while the tilt angles above this are used whentowing the marine vessel 10 or transporting it by land.

Tilt-trim actuators 56, 58, such as hydraulic or pneumaticpiston-cylinders or electric linear actuators, are provided for rotatingthe marine propulsion devices 14, 16 about their tilt-trim axes 20, 24in response to tilt-trim inputs to the keypad(s) 54. Note that in someexamples, tilt actuators that are separate from the trim actuators 56,58 might be provided. First and second tilt-trim sensors 60, 62 on thefirst and second marine propulsion devices 14, 16, respectively, measurefirst and second tilt-trim positions of the respective first and secondmarine propulsion devices 14, 16. For example, tilt-trim sensors 60, 62measure relative positions between two parts associated with thetilt-trim actuators 56, 58. The tilt-trim sensors 60, 62 may be any typeof sensor known to those having ordinary skill in the art, for exampleHall Effect sensors or rheostat sensors. In another example, the firstand second tilt-trim sensors 60, 62 are 3-axis accelerometers. Theaccelerometers may be linear and/or angular accelerometers. In oneexample, the accelerometers are MEMS accelerometers. In still anotherexample, 3-axis gyrometers are used to measure the tilt-trim position ofeach marine propulsion device 14, 16. The gyrometers detect changes inrotational attributes of the marine propulsion devices 14, 16, forexample by measuring changes in rate of rotation (i.e., angularvelocity). The gyrometers may be MEMS gyrometers, dynamically tunedgyrometers, or any other type of gyrometer known to those havingordinary skill in the art.

A steering actuator 63, 64, such as a hydraulic, pneumatic, or electricactuator, is provided for steering each marine propulsion device 14, 16in response to inputs from the joystick 48 or the steering wheel 50.First and second steering sensors 66, 68 on the first and second marinepropulsion devices 14, 16, respectively, measure first and secondsteering positions of the respective first and second marine propulsiondevices 14, 16. The steering sensors 66, 68 may also be Hall Effectsensors or potentiometers. In other examples, a steering sensor is alsoprovided at the steering wheel 50 for additional steering information.

FIG. 2 shows an instance in which there are only two marine propulsiondevices 14, 16, but it should be understood that similar actuators andsensors are provided for each marine propulsion device if more than twomarine propulsion devices are provided on the marine vessel 10.Additionally, note that if the first and second marine propulsiondevices 14, 16 are pod drives or inboard motors, they do not tilt ortrim, and tilt/trim sensors and actuators are not provided, in whichcase the algorithms described herein below utilize steering positioninformation rather than both steering position information and tilt/trimposition information.

The control modules, including HCM 40 and ECMs 42, 44, are programmableand each includes a processor and a memory, although for purposes ofsimplicity the processor 72 and memory 74 are shown in conjunction withHCM 40 only. The control modules 40, 42, 44 can be located anywhere inthe marine propulsion system 12 and/or located remote from the marinepropulsion system 12 and can communicate with various components of themarine vessel 10 via a peripheral interface and wired and/or wirelesslinks. Portions of the method disclosed herein below can be carried outby a single control module or by several separate control modules inconjunction with one another.

In some examples, each control module 40, 42, 44 may include a computingsystem that includes a processing system, storage system, software, andinput/output (I/O) interfaces for communicating with peripheral devices.The systems may be implemented in hardware and/or software that carriesout a programmed set of instructions. For example, the processing systemloads and executes software from the storage system, such as softwareprogrammed with a global wake method, which directs the processingsystem to operate as described herein below in further detail. Thecomputing system may include one or more processors, which may becommunicatively connected. The processing system can comprise amicroprocessor, including a control unit and a processing unit, andother circuitry, such as semiconductor hardware logic, that retrievesand executes software from the storage system. The processing system canbe implemented within a single processing device but can also bedistributed across multiple processing devices or sub-systems thatcooperate according to existing program instructions. The processingsystem can include one or many software modules comprising sets ofcomputer executable instructions for carrying out various functions asdescribed herein.

As used herein, the term “control module” may refer to, be part of, orinclude an application specific integrated circuit (ASIC); an electroniccircuit; a combinational logic circuit; a field programmable gate array(FPGA); a processor (shared, dedicated, or group) that executes code;other suitable components that provide the described functionality; or acombination of some or all of the above, such as in a system-on-chip(SoC). A control module may include memory (shared, dedicated, or group)that stores code executed by the processing system. The term “code” mayinclude software, firmware, and/or microcode, and may refer to programs,routines, functions, classes, and/or objects. The term “shared” meansthat some or all code from multiple control modules may be executedusing a single (shared) processor. In addition, some or all code frommultiple control modules may be stored by a single (shared) memory. Theterm “group” means that some or all code from a single control modulemay be executed using a group of processors. In addition, some or allcode from a single control module may be stored using a group ofmemories.

The storage system can comprise any storage media readable by theprocessing system and capable of storing software. The storage systemcan include volatile and non-volatile, removable and non-removable mediaimplemented in any method or technology for storage of information, suchas computer-readable instructions, data structures, software programmodules, or other data. The storage system can be implemented as asingle storage device or across multiple storage devices or sub-systems.The storage system can include additional elements, such as a memorycontroller capable of communicating with the processing system.Non-limiting examples of storage media include random access memory,read-only memory, magnetic discs, optical discs, flash memory, virtualand non-virtual memory, various types of magnetic storage devices, orany other medium which can be used to store the desired information andthat may be accessed by an instruction execution system. The storagemedia can be a transitory storage media or a non-transitory storagemedia such as a non-transitory tangible computer readable medium.

The control modules 40, 42, 44 communicate with one another and with theone or more components of the marine propulsion system 12 via the I/Ointerfaces and a communication link 70, which can be a wired or wirelesslink. The control modules 40, 42, 44 are capable of monitoring andcontrolling one or more operational characteristics of the marinepropulsion system 12 and its various subsystems by sending and receivingcontrol signals via the communication link 70. In one example, thecommunication link 70 is a controller area network (CAN) bus, but othertypes of links could be used. It should be noted that the extent ofconnections of the communication link 70 shown herein is for schematicpurposes only, and the communication link 70 in fact providescommunication between the control modules 40, 42, 44 and each of theperipheral devices noted herein, although not every connection is shownin the drawing for purposes of clarity.

As boaters demand more power on their boats, there has been a tendencyto install more and/or larger marine propulsion devices on a singlemarine vessel. This is especially easy to do with an outboard motor,which does not require changes to the vessel's hull to install. Throughresearch and development, the present inventors have determined that asmore and larger marine propulsion devices are mounted on a single marinevessel's transom, the likelihood that they might interfere with oneanother while moving increases. The likelihood of interference(collision) increases when one or more of the marine propulsion devicesis not turned ON. If all marine propulsion devices on the transom areturned ON and are manually controlled, they are generally all steeredtogether. Although tilt/trim can be individually controlled,simultaneous steering is likely to prevent any collision. If all marinepropulsion devices on the transom are turned ON and are automaticallycontrolled, the automatic control algorithm is generally calibrated toprevent collision between the marine propulsion devices. However, iffewer than all of the marine propulsion devices are steered and/ortilted/trimmed (whether they are ON or not), the likelihood that thosesteered and/or tilted/trimmed marine propulsion devices will collidewith a stationary marine propulsion device that is OFF increases, as theOFF marine propulsion device is not being steered simultaneously.Therefore, the present inventors have developed systems and methods forturning ON the ECM of an OFF marine propulsion device that is notsteered and/or tilted/trimmed, so that the previously OFF marinepropulsion device can report its position for comparison with theintended or anticipated position of the marine propulsion device that isbeing steered and/or tilted/trimmed.

FIG. 3 shows an example in which two helm control modules 40 a, 40 b areprovided, one associated with each marine propulsion device's ECM 42,44. Each HCM 40 a, 40 b includes a microprocessor 76 a, 76 b in signalcommunication with a key input 78, 80 by way of respective lines 82, 84.The key inputs 78, 80 are initiated by the operator of the marinepropulsion system 12 by, for example, inserting a key into a slot andturning the key within the slot to an ON position. Alternatively, a keyfob can be brought near a key reader, and an ON button pressed or an ONtouch screen selection made. The respective engines 26, 28 in eachmarine propulsion device 14, 16 can similarly be started by turning therespective keys to START positions, or by selecting respectiveSTART/STOP buttons or display screen options. It should be understoodthat each key input 78, 80 is individually associated with a respectiveECM 42 or 44. For instance, key input 78 being turned ON will turn on(or “wake up”) ECM 42, while key input 80 being turned ON will turn onECM 44. The signals along lines 82 and 84 are interpreted by therespective ECMs 42, 44 as commands to turn their power ON and to providenormal steering, trim, diagnostic, and other functionality to the marinepropulsion devices 14, 16.

When the key input is received from either 78 or 80, a signal is sentover line 86 to the operation console 38 and to each of the controlslocated there. Thus, the interactive display screen 46, joystick 48,steering wheel 50, and throttle/shift levers 52 are all woken up(provided with electrical power) in order that they may be used to inputcontrol signals to the HCMs 40 a, 40 b. Additionally, according to thepresent disclosure, in response to one of the first and second marinepropulsion devices 14, 16 being keyed ON at key input 78 or 80, therespective first or second control module 42, 44 of the other of thefirst and second marine propulsion devices 14, 16 is turned ON. This isshown by the signal over line 88. The signal over line 88 is interpretedby the ECMs 42, 44 as a command to power ON, but, in one example, toprovide communication only of specific parameters and control only ofspecific outputs, rather than to provide full functionality as if theECM 42 or 44 had been keyed ON via line 82 or 84.

In the present example, each ECM 42, 44 has a high side output (HSO) 90,92 capable of sending a +12V signal over line 88 to wake the other ECM42, 44. The connection between the HSOs 90, 92 and the line 88 can bemade internally to the respective ECM 42, 44 or in the respective marinepropulsion device's wiring harness. In the present example, the ECM 42or 44 that is keyed ON asserts the +12V output signal from HSO 90 or 92over line 88 in response to receiving the respective input signal overline 82 or 84. Such an input/output causal chain can be accomplished byway of the microprocessors 76 a, 76 b, which are in signal communicationwith one another, or by way of an OR-gate diode circuit connecting theline 82 to the HSO 92 and the line 84 to the HSO 90.

Alternatively, in response to one of the first and second marinepropulsion devices 14, 16 being commanded to rotate about at least oneof its respective first or second steering axis 18, 22 and itsrespective first or second tilt-trim axis 20, 24 (see inputs 94, 96),the respective first or second control module 42, 44 of the other of thefirst and second marine propulsion devices 14, 16 is turned ON. In otherwords, the ECM 42 or 44 of the marine propulsion device 14 or 16 that isbeing commanded to turn, tilt, or trim will assert the +12V outputsignal over line 88 to provide power to the ECM 42 or 44 of the othermarine propulsion device 14 or 16 that is not being commanded to turn,tilt, or trim. This “global wake” feature could be provided when the ECMof the steered or tilted/trimmed marine propulsion device is ON, but theECM of the other marine propulsion device is OFF, or only when both ECMs42, 44 are currently OFF, or even when the ECMs 42, 44 are both alreadyON. If both of the ECMs 42, 44 are OFF when the steering or tilt-trimcommand is received, in response to the one of the first and secondmarine propulsion devices 14, 16 being commanded to rotate about the atleast one of its respective first or second steering axis 18, 22 and itsrespective first or second tilt-trim axis 20, 24, the respective firstor second control module 42, 44 of the one of the first and secondmarine propulsion devices 14, 16 is turned ON. Note that when the ECMs42, 44 are turned on, the corresponding engines 26, 28 are notnecessarily started, unless they have otherwise been commanded to start.Note also that when an ECM is turned ON via a signal over line 88,certain functions are not turned on, such as fuel pumps, electricalloads, and diagnostics. This prevents the marine propulsion device 14 or16 from using more energy than needed to report its steering andtilt/trim position, seeing as its alternator is not on (because theengine is not running) to recharge its battery.

Turning on the ECM 42 or 44 of the marine propulsion device 14, or 16that is not keyed ON or that is not commanded to steer, tilt, or trimprovides an advantage over known prior art because the relativepositioning of the two marine propulsion devices 14, 16 can be comparedin order to prevent collisions between the two marine propulsion devices14, 16 and potential damage thereto. As noted herein above, the firstand second control modules 42 44 receive the first and second steeringpositions and the first and second tilt-trim positions, respectively,from the first and second steering sensors 66, 68 and the first andsecond tilt-trim sensors 60, 62, respectively. However, the ECMs 42, 44are only able to receive and communicate this information when the ECMs42, 44 are powered ON. Thus, it is possible for ECM 42 to report thesteering position and/or tilt-trim position of the first marinepropulsion device 14 when it is powered ON, and for ECM 44 to report thesteering position and/or tilt-trim position of the second marinepropulsion device 16 when it is powered ON.

After steering and/or tilt-trim positions have been reported, inresponse to determining that rotating the one of the first and secondmarine propulsion devices 14, 16 about its respective first or secondsteering axis 18, 22 will cause the one of the first and second marinepropulsion devices 14, 16 to collide with the other of the first andsecond marine propulsion devices 14, 16 based on at least one of therespective first or second steering position and the respective first orsecond tilt-trim position of the other of the first and second marinepropulsion devices 14, 16, the one of the first and second marinepropulsion devices 14, 16 is at least temporarily prevented fromrotating about its respective first or second steering axis 18, 22.Similarly, in response to determining that rotating the one of the firstand second marine propulsion devices 14, 16 about its respective firstor second tilt-trim axis 20, 24 will cause the one of the first andsecond marine propulsion devices 14, 16 to collide with the other of thefirst and second marine propulsion devices 14, 16 based on at least oneof the respective first or second steering position and the respectivefirst or second tilt-trim position of the other of the first and secondmarine propulsion devices 14, 16, the one of the first and second marinepropulsion devices 14, 16 is at least temporarily prevented fromrotating about its respective first or second tilt-trim axis. In bothinstances, the requested or anticipated steering position or tilt-trimposition of the one of the first and second marine propulsion devices14, 16 that was commanded to rotate could also be taken into account andcompared to the existing steering and/or tilt-trim position of the otherof the marine propulsion devices 14, 16 that was not commanded torotate.

In order to determine if the steering position and the tilt-trimposition of the other of the first and second marine propulsion devices14, 16 that was not commanded to rotate will present a potentialcollision problem, the measured steering positions and/or tilt-trimpositions reported to each ECM 42, 44 need to be shared, i.e., the firstand second control modules 42, 44 need to be in signal communicationwith each other. These measurements could be reported back to themicroprocessors 76 s, 76 b of the HCMs 40 a, 40 b, either of which coulddetermine if a collision is likely and output a command to the ECM 42 or44 to temporarily prevent the marine propulsion device 14 or 16 fromrotating. Alternatively, the ECMs 42, 44 could be directlycommunicatively connected to one another, and either ECM 42 or 44 coulddetermine if a collision is likely and output a command to temporarilyprevent the marine propulsion device 14 or 16 from rotating.Additionally or alternatively, these measurements could be relayed to atelematics module 98, which can also gather information about the numberof hours the engines 26, 28 have been running, the voltage of batteriesin each marine propulsion device 14, 16, the level of fuel in fuel tanksfor each marine propulsion device 14, 16, etc. and provide thisinformation to the operator via the interactive display screen 46. Inone example, the telematics module 98 is the module that performs thecomparisons noted herein and determines whether the marine propulsiondevices 14, 16 will collide if a commanded steering or tilt-trimmaneuver is carried out.

In other examples, instead of immediately preventing the marinepropulsion device 14, 16 that was commanded to rotate from rotating atall, even temporarily, the marine propulsion device 14, 16 may bepermitted to rotate in the direction of the steering and/or tilt-trimcommand until it reaches a position after which further rotation wouldcause collision with the other marine propulsion device 14, 16 that wasnot commanded to rotate. After the marine propulsion device 14 or 16reaches this steering and/or tilt-trim limit, which is predeterminedbased on the position of the other marine propulsion device 14 or 16,the marine propulsion device 14 or 16 that was rotating may betemporarily prevented from further rotation. By way of example, if threemarine propulsion devices are provided on the transom of the marinevessel 10, and only the middle marine propulsion device was steeredand/or tilted/trimmed, the operator could be given an option (asdescribed below) to steer the two outer marine propulsion devicesoutwardly and trim them up. If the operator chose not to undertake thisaction, the movement of the middle marine propulsion device could beautomatically limited to moving within a boundary (limits) within whichit would not collide with the two outer marine propulsion devices.

In either of the above instances, i.e., whether the marine propulsiondevice is temporarily preventing from rotating with or without rotatingto a predetermined limit beforehand, the display screen 46 can beutilized to permit rotation thereafter. As shown in FIGS. 1 and 2, thedisplay screen 46 is communicatively coupled to the first and secondcontrol modules 42, 44. An alert is generated on the display screen 46in response to:

-   -   (a) the one of the first and second marine propulsion devices        14, 16 being commanded to rotate about the at least one of its        respective first or second steering axis 18, 22 and its        respective first or second tilt-trim axis 20, 24; and    -   (b) determining that rotating the one of the first and second        marine propulsion devices 14, 16 about the at least one of its        respective first or second steering axis 18, 22 and its        respective first or second tilt-trim axis 20, 24 will cause the        one of the first and second marine propulsion devices 14, 16 to        collide with the other of the first and second marine propulsion        devices 14, 16 based on at least one of the respective first or        second steering position and the respective first or second        tilt-trim position of the other of the first and second marine        propulsion devices 14, 16.        As noted herein above, the determination in (b) may also be made        based on the requested or anticipated first or second steering        position and first or second tilt-trim position of the one of        the first and second marine propulsion devices 14, 16 that was        commanded to rotate.

In one example, the alert provides an option to trim the other of thefirst and second marine propulsion devices 14, 16 up. This allows themarine propulsion device that was not initially commanded to rotate tobe moved up and out of the way of steering and tilting/trimming of themarine propulsion device that was initially commanded to rotate. Thismight be helpful if, for example, the primary steering actuator 63 or 64on one of the marine propulsion devices 14 or 16 is not working, and abackup steering actuator is instead being used. Because backup steeringactuators may be much slower than the primary steering actuator 63 or64, the steering speed of the functioning primary steering actuator onthe other marine propulsion device would be limited. An alert could letthe operator know that if he or she trimmed the marine propulsion devicewith the non-functioning steering actuator up out of the way, fullsteering speed would be available from the remainder of the marinepropulsion devices.

In another example, the alert provides an option to steer the other ofthe first and second marine propulsion devices 14, 16 away from the oneof the first and second marine propulsion devices 14, 16 that wasinitially commanded to rotate. This allows the marine propulsion devicethat was not initially commanded to rotate to be moved laterally out ofthe way of steering and/or tilting/trimming of the marine propulsiondevice that was initially commanded to rotate.

In either example, the alert might allow the operator to select thecorrective action directly from the interactive display screen 46. Inother examples, the alert might instruct the operator to use thesteering wheel 50 or joystick 48 to steer the other marine propulsiondevice 14, 16 out of the way, or to use the appropriate trim button 54 ato trim the other marine propulsion device 14, 16 up out of the way. Instill other examples, the display screen 46 might instruct the operatorboth to steer the other marine propulsion device 14, 16 outwardly and totrim the other marine propulsion device 14, 16 up. After the othermarine propulsion device 14, 16 is steered and/or tilted/trimmed out ofthe way of the marine propulsion device 14, 16 that was initiallycommanded to rotate, the marine propulsion device that was initiallycommanded to rotate could be automatically rotated according to theinitial steering and/or tilt-trim command. Alternatively, the displayscreen 46 may present the operator with an option to continue to steerand/or tilt-trim the marine propulsion device that was initiallycommanded to rotate according to the initial command, or may instructthe operator to again input the initial steering command via thejoystick 48 or steering wheel 50 or to again input the initial tilt-trimcommand via the keypad 54. In still another example, the operator may berequired to re-input the initial command without any prompts.

In yet another example, the other of the first and second marinepropulsion devices 14, 16 that was not initially commanded to steerand/or tilt-trim is automatically trimmed up and steered away from theone of the first and second marine propulsion devices 14, 16 in responseto:

-   -   (a) the one of the first and second marine propulsion devices        14, 16 being commanded to rotate about the at least one of its        respective first or second steering axis 18, 22 and its        respective first or second tilt-trim axis 20, 24; and    -   (b) determining that rotating the one of the first and second        marine propulsion devices 14, 16 about the at least one of its        respective first or second steering axis 18, 22 and its        respective first or second tilt-trim axis 20, 24 will cause the        one of the first and second marine propulsion devices 14, 16 to        collide with the other of the first and second marine propulsion        devices 14, 16 based on at least one of the respective first or        second steering position and the respective first or second        tilt-trim position of the other of the first and second marine        propulsion devices.        As noted herein above, the determination in (b) may also be made        based on the requested or anticipated first or second steering        position and first or second tilt-trim position of the one of        the first and second marine propulsion devices 14, 16 that was        commanded to rotate. This embodiment may include automatic        steering and/or tilting/trimming of the marine propulsion device        that was initially commanded to rotate after the other marine        propulsion device is moved out of the way. This embodiment could        be accompanied by alerts on the display screen 46 and/or audio        or haptic alerts that inform the operator that the other of the        marine propulsion devices 14, 16 is being moved without any        corresponding input on the operator's part. Such alerts would        prevent the marine propulsion system 12 from taking unexpected        action that the operator did not intend without first alerting        the operator. This automatic feature, if provided, could be        capable of being toggled ON or OFF by the operator via a button        or display screen option at the operation console 38.

Now turning to FIG. 4, a method 400 for a marine propulsion system 12for a marine vessel 10 will be described. The method includesdetermining at least one of the following: (a) whether a first marinepropulsion device 14 rotatable with respect to the marine vessel 10about at least one of a first steering axis 18 and a first tilt-trimaxis 20 is keyed ON (see 402); (b) whether a second marine propulsiondevice 16 rotatable with respect to the marine vessel 10 about at leastone of a second steering axis 22 and a second tilt-trim axis 24 is keyedON (see 404); (c) whether the first marine propulsion device 14 iscommanded to rotate about at least one of its first steering axis 18 andits first tilt-trim axis 20 (see 406); and (d) whether the second marinepropulsion device 16 is commanded to rotate about at least one of itssecond steering axis 22 and its second tilt-trim axis 24 (see 408). IfNO to all of 402, 404, 406, and 408 (or if NO to whicheverdeterminations are made), the method returns to 402.

As shown at 410, in response to at least one of (a), (b), (c), and (d)being true (i.e., YES at 402, 404, 406, or 408), the method includesturning on a first control module 42 controlling operation of the firstmarine propulsion device 14 and a second control module 44 controllingoperation of the second marine propulsion device 16. Note that thedeterminations at 402-408 can be made simultaneously or in any order,and the order shown herein is not limiting on the scope of the presentdisclosure. Note also that more than one of 402-408 may be true (YES) atone time and the method will continue to 410. Additionally, note thatnot all of the determinations at 402-408 need be made, and instead onlyone, two, or three of the determinations can be made according to theprogramming of the control algorithm.

The method may include measuring at least one of first and secondsteering positions of the respective first and second marine propulsiondevices 14, 16 with steering sensors 66, 68 and first and secondtilt-trim positions of the respective first and second marine propulsiondevices 14, 16 with tilt-trim sensors 60, 62. The method may alsoinclude receiving the at least one of the first and second steeringpositions and the first and second tilt-trim positions at the first andsecond control modules 42, 44, respectively. In one example, the methodincludes measuring the first and second tilt-trim positions of therespective first and second marine propulsion devices 14, 16 withrespective first and second accelerometers.

The method may include receiving a steering command to rotate one of thefirst and second marine propulsion devices 14, 16 about its respectivefirst or second steering axis 18, 22; determining whether rotating theone of the first and second marine propulsion devices 14, 16 accordingto the steering command will cause the one of the first and secondmarine propulsion devices 14, 16 to collide with the other of the firstand second marine propulsion devices 14, 16 based on at least one of therespective first or second steering position and the respective first orsecond tilt-trim position of the other of the first and second marinepropulsion devices 14, 16; and in response to determining that rotatingthe one of the first and second marine propulsion devices 14, 16according to the steering command will cause a collision, at leasttemporarily preventing the one of the first and second marine propulsiondevices 14, 16 from rotating about its respective first or secondsteering axis 18, 22. Similarly, the method may include receiving atilt-trim command to rotate one of the first and second marinepropulsion devices 14, 16 about its respective first or second tilt-trimaxis 20, 24; determining whether rotating the one of the first andsecond marine propulsion devices 14, 16 according to the tilt-trimcommand will cause the one of the first and second marine propulsiondevices 14, 16 to collide with the other of the first and second marinepropulsion devices 14, 16 based on at least one of the respective firstor second steering position and the respective first or second tilt-trimposition of the other of the first and second marine propulsion devices14, 16; and in response to determining that rotating the one of thefirst and second marine propulsion devices 14, 16 according to thetilt-trim command will cause a collision, at least temporarilypreventing the one of the first and second marine propulsion devices 14,16 from rotating about its respective first or second tilt-trim axis 20,24. As noted herein above, these determinations may also be made basedon the requested or anticipated first or second steering position andfirst or second tilt-trim position of the one of the first and secondmarine propulsion devices 14, 16 that was commanded to rotate.

The method may also include generating an alert in response to:

-   -   (1) one of the first and second marine propulsion devices 14, 16        being commanded to rotate about at least one of its respective        first or second steering axis 18, 22 and its respective first or        second tilt-trim axis 20, 24; and    -   (2) determining that rotating the one of the first and second        marine propulsion devices 14, 16 about the at least one of its        respective first or second steering axis 18, 22 and its        respective first or second tilt-trim axis 20, 24 will cause the        one of the first and second marine propulsion devices 14, 16 to        collide with the other of the first and second marine propulsion        devices 14, 16 based on at least one of the respective first or        second steering position and the respective first or second        tilt-trim position of the other of the first and second marine        propulsion devices 14, 16.        The method may include providing the operator of the marine        propulsion system 12 an option on the display screen 46 to trim        the other of the first and second marine propulsion devices 14,        16 up in response to (1) and (2). The method may include        providing the operator of the marine propulsion system 12 an        option on the display screen 46 to steer the other of the first        and second marine propulsion devices 14, 16 away from the one of        the first and second marine propulsion devices 14, 16 in        response to (1) and (2).

The method may alternatively include automatically trimming one of thefirst and second marine propulsion devices 14, 16 up and steering theone of the first and second marine propulsion devices 14, 16 away fromthe other of the first and second marine propulsion devices 14, 16 inresponse to:

-   -   (a) the other of the first and second marine propulsion devices        14, 16 being commanded to rotate about at least one of its        respective first or second steering axis 18, 22 and its        respective first or second tilt-trim axis 20, 24; and    -   (b) determining that rotating the other of the first and second        marine propulsion devices 14, 16 about the at least one of its        respective first or second steering axis 18, 22 and its        respective first or second tilt-trim axis 20, 24 will cause the        other of the first and second marine propulsion devices 14, 16        to collide with the one of the first and second marine        propulsion devices 14, 16 based on at least one of the        respective first or second steering position and the respective        first or second tilt-trim position of the one of the first and        second marine propulsion devices 14, 16.

In order to determine if movement of the one of the marine propulsiondevices that is commanded to steer and/or tilt/trim will cause acollision with the other of the marine propulsion devices, as notedherein above, the control module 40, 40 a, 40 b, 42, 44 will need toknow the position of the stationary marine propulsion device. Thecontrol module 40, 40 a, 40 b, 42, 44 would also be able to predict theanticipated position of the moving marine propulsion device based on itscurrent position and a commanded positional change, or based on acommanded desired steering or tilt/trim angle. The control module 40, 40a, 40 b, 42, 44 may also have other data saved in its memory, such asthe height of the marine propulsion devices on the transom, the mountingdistance between the marine propulsion devices, and the dimensions (suchas length) of the marine propulsion devices. The algorithms thatdetermine whether collision would be likely may be programmed for theworst case scenario, such that there is a safety factor built in. In oneexample, the method of U.S. Pat. No. 8,818,587 may be used to determineif collision is likely.

In the present description, certain terms have been used for brevity,clarity, and understanding. No unnecessary limitations are to be impliedtherefrom beyond the requirement of the prior art because such terms areused for descriptive purposes only and are intended to be broadlyconstrued. The different systems and methods described herein may beused alone or in combination with other systems and methods. Variousequivalents, alternatives, and modifications are possible within thescope of the appended claims. Each limitation in the appended claims isintended to invoke interpretation under 35 USC § 112(f), only if theterms “means for” or “step for” are explicitly recited in the respectivelimitation.

The functional block diagrams, operational sequences, and flow diagramsprovided in the Figures are representative of exemplary architectures,environments, and methodologies for performing novel aspects of thedisclosure. While, for purposes of simplicity of explanation, themethodologies included herein may be in the form of a functionaldiagram, operational sequence, or flow diagram, and may be described asa series of acts, it is to be understood and appreciated that themethodologies are not limited by the order of acts, as some acts may, inaccordance therewith, occur in a different order and/or concurrentlywith other acts from that shown and described herein. For example, thoseskilled in the art will understand and appreciate that a methodology canalternatively be represented as a series of interrelated states orevents, such as in a state diagram. Moreover, not all acts illustratedin a methodology may be required for a novel implementation.

What is claimed is:
 1. A marine propulsion system for a marine vessel,the marine propulsion system comprising: a first marine propulsiondevice rotatable with respect to the marine vessel about at least one ofa first steering axis and a first tilt-trim axis; a second marinepropulsion device rotatable with respect to the marine vessel about atleast one of a second steering axis and a second tilt-trim axis; a firstelectronic control module controlling operation of a first engine of thefirst marine propulsion device; and a second electronic control modulecontrolling operation of a second engine of the second marine propulsiondevice; wherein, in response to one of the first and second marinepropulsion devices being commanded to rotate about at least one of itsrespective first or second steering axis and its respective first orsecond tilt-trim axis, the respective first or second electronic controlmodule of the other of the first and second marine propulsion devices isprovided with sufficient voltage to turn the respective first or secondelectronic control module of the other of the first and second marinepropulsion devices ON.
 2. The marine propulsion system of claim 1,further comprising at least one of: first and second steering sensors onthe first and second marine propulsion devices, respectively, thatmeasure first and second steering positions of the respective first andsecond marine propulsion devices; and first and second tilt-trim sensorson the first and second marine propulsion devices, respectively, thatmeasure first and second tilt-trim positions of the respective first andsecond marine propulsion devices; wherein the first and secondelectronic control modules receive at least one of the first and secondsteering positions and the first and second tilt-trim positions,respectively; and wherein the first and second electronic controlmodules are in signal communication with each other.
 3. The marinepropulsion system of claim 2, wherein, in response to determining thatrotating the one of the first and second marine propulsion devices aboutits respective first or second steering axis will cause the one of thefirst and second marine propulsion devices to collide with the other ofthe first and second marine propulsion devices based on at least one ofthe respective first or second steering position and the respectivefirst or second tilt-trim position of the other of the first and secondmarine propulsion devices, the one of the first and second marinepropulsion devices is at least temporarily prevented from rotating aboutits respective first or second steering axis.
 4. The marine propulsionsystem of claim 2, wherein, in response to determining that rotating theone of the first and second marine propulsion devices about itsrespective first or second tilt-trim axis will cause the one of thefirst and second marine propulsion devices to collide with the other ofthe first and second marine propulsion devices based on at least one ofthe respective first or second steering position and the respectivefirst or second tilt-trim position of the other of the first and secondmarine propulsion devices, the one of the first and second marinepropulsion devices is at least temporarily prevented from rotating aboutits respective first or second tilt-trim axis.
 5. The marine propulsionsystem of claim 2, wherein the first and second tilt-trim sensors areaccelerometers.
 6. The marine propulsion system of claim 2, furthercomprising a display screen communicatively coupled to the first andsecond electronic control modules; wherein an alert is generated on thedisplay screen in response to: (a) the one of the first and secondmarine propulsion devices being commanded to rotate about the at leastone of its respective first or second steering axis and its respectivefirst or second tilt-trim axis; and (b) determining that rotating theone of the first and second marine propulsion devices about the at leastone of its respective first or second steering axis and its respectivefirst or second tilt-trim axis will cause the one of the first andsecond marine propulsion devices to collide with the other of the firstand second marine propulsion devices based on at least one of therespective first or second steering position and the respective first orsecond tilt-trim position of the other of the first and second marinepropulsion devices.
 7. The marine propulsion system of claim 6, whereinthe alert provides an option to trim the other of the first and secondmarine propulsion devices up.
 8. The marine propulsion system of claim6, wherein the alert provides an option to steer the other of the firstand second marine propulsion devices away from the one of the first andsecond marine propulsion devices.
 9. The marine propulsion system ofclaim 2, wherein the other of the first and second marine propulsiondevices is automatically trimmed up and steered away from the one of thefirst and second marine propulsion devices in response to: (a) the oneof the first and second marine propulsion devices being commanded torotate about the at least one of its respective first or second steeringaxis and its respective first or second tilt-trim axis; and (b)determining that rotating the one of the first and second marinepropulsion devices about the at least one of its respective first orsecond steering axis and its respective first or second tilt-trim axiswill cause the one of the first and second marine propulsion devices tocollide with the other of the first and second marine propulsion devicesbased on at least one of the respective first or second steeringposition and the respective first or second tilt-trim position of theother of the first and second marine propulsion devices.
 10. The marinepropulsion system of claim 1, wherein, in response to the one of thefirst and second marine propulsion devices being commanded to rotateabout the at least one of its respective first or second steering axisand its respective first or second tilt-trim axis, the respective firstor second electronic control module of the one of the first and secondmarine propulsion devices is turned ON.
 11. The marine propulsion systemof claim 1, wherein, in response to one of the first and second marinepropulsion devices being keyed ON, the respective first or secondelectronic control module of the other of the first and second marinepropulsion devices is turned ON.
 12. A method for a marine propulsionsystem for a marine vessel, the method being carried out by a controlmodule and comprising: determining at least one of the following: (a)whether a first marine propulsion device rotatable with respect to themarine vessel about at least one of a first steering axis and a firsttilt-trim axis is keyed ON; (b) whether a second marine propulsiondevice rotatable with respect to the marine vessel about at least one ofa second steering axis and a second tilt-trim axis is keyed ON; (c)whether the first marine propulsion device is commanded to rotate aboutat least one of its first steering axis and its first tilt-trim axis;and (d) whether the second marine propulsion device is commanded torotate about at least one of its second steering axis and its secondtilt-trim axis; and in response to at least one of (a), (b), (c), and(d) being true, providing sufficient voltage to turn on a firstelectronic control module controlling operation of a first engine of thefirst marine propulsion device and a second electronic control modulecontrolling operation of a second engine of the second marine propulsiondevice.
 13. The method of claim 12, further comprising: measuring atleast one of first and second steering positions and first and secondtilt-trim positions of the respective first and second marine propulsiondevices; and receiving the at least one of the first and second steeringpositions and the first and second tilt-trim positions at the first andsecond electronic control modules, respectively.
 14. The method of claim13, further comprising: receiving a steering command to rotate one ofthe first and second marine propulsion devices about its respectivefirst or second steering axis; determining whether rotating the one ofthe first and second marine propulsion devices according to the steeringcommand will cause the one of the first and second marine propulsiondevices to collide with the other of the first and second marinepropulsion devices based on at least one of the respective first orsecond steering position and the respective first or second tilt-trimposition of the other of the first and second marine propulsion devices;and in response to determining that rotating the one of the first andsecond marine propulsion devices according to the steering command willcause a collision, at least temporarily preventing the one of the firstand second marine propulsion devices from rotating about its respectivefirst or second steering axis.
 15. The method of claim 13, furthercomprising: receiving a tilt-trim command to rotate one of the first andsecond marine propulsion devices about its respective first or secondtilt-trim axis; determining whether rotating the one of the first andsecond marine propulsion devices according to the tilt-trim command willcause the one of the first and second marine propulsion devices tocollide with the other of the first and second marine propulsion devicesbased on at least one of the respective first or second steeringposition and the respective first or second tilt-trim position of theother of the first and second marine propulsion devices; and in responseto determining that rotating the one of the first and second marinepropulsion devices according to the tilt-trim command will cause acollision, at least temporarily preventing the one of the first andsecond marine propulsion devices from rotating about its respectivefirst or second tilt-trim axis.
 16. The method of claim 13, furthercomprising measuring the first and second tilt-trim positions of therespective first and second marine propulsion devices with respectivefirst and second accelerometers.
 17. The method of claim 13, furthercomprising generating an alert in response to: (1) one of the first andsecond marine propulsion devices being commanded to rotate about atleast one of its respective first or second steering axis and itsrespective first or second tilt-trim axis; and (2) determining thatrotating the one of the first and second marine propulsion devices aboutthe at least one of its respective first or second steering axis and itsrespective first or second tilt-trim axis will cause the one of thefirst and second marine propulsion devices to collide with the other ofthe first and second marine propulsion devices based on at least one ofthe respective first or second steering position and the respectivefirst or second tilt-trim position of the other of the first and secondmarine propulsion devices.
 18. The method of claim 17, furthercomprising providing an operator of the marine propulsion system anoption on a display screen to trim the other of the first and secondmarine propulsion devices up in response to (1) and (2).
 19. The methodof claim 17, further comprising providing an operator of the marinepropulsion system an option on a display screen to steer the other ofthe first and second marine propulsion devices away from the one of thefirst and second marine propulsion devices in response to (1) and (2).20. The method of claim 13, further comprising automatically trimmingone of the first and second marine propulsion devices up and steeringthe one of the first and second marine propulsion devices away from theother of the first and second marine propulsion devices in response to:(a) the other of the first and second marine propulsion devices beingcommanded to rotate about at least one of its respective first or secondsteering axis and its respective first or second tilt-trim axis; and (b)determining that rotating the other of the first and second marinepropulsion devices about the at least one of its respective first orsecond steering axis and its respective first or second tilt-trim axiswill cause the other of the first and second marine propulsion devicesto collide with the one of the first and second marine propulsiondevices based on at least one of the respective first or second steeringposition and the respective first or second tilt-trim position of theone of the first and second marine propulsion devices.